Abstract:Objective To discuss the methods of reduction,fixation,and postoperative recovery in the treatment for adult Neer Ⅳ proximal humerus fracture using the locking plate internal fixation,and to observe the treatment effect.Methods The open reduction and locking plate internal fixation were used to treat adult Neer Ⅳ proximal humerus fractures.This treatment had been used in 26 cases,in which 18 cases were associated with humeral head dislocation.In the operation,the junction between the deltoid and the pectoralis major was exposed.Then based on the integrity of soft tissues like the shoulder articular capsule,the extracapsular reduction method or intracapsular reduction method was adopted.We restored the dislocated humeral head to its normal position.Then fractures were reducted based on circumstances such as bone displacement.K-wires were usedfor temporary fixation.We placed the anatomical lock plate at the lateral sideof proximal humerus to fix the fracture.After operation,patients underwent strict rehabilitation training under the therapist's guidance.Results Follow-up of patients ranges from 12 months to 5 years with anaverage of 38 months.Among them,three patients hadmuscular atrophy in the shoulder.And the shoulder was not of good shape.Allshoulder joints have recovered in 12 weeks after operation excepttwo.No patients suffered from shoulder joint re-dislocation or nonunion.Humerus height loss occurred in four cases.In one case,the humeral head screw protruded from the articular surface.In two cases,patients developed humeral head ischemic necrosis respectively after six months and 15 months.The necrosis rate was 7.69%.In the last follow-up,ASES rates of the 26 patients ranged from 62 to 100 with an average of 92.8;and their Constant-Murley rates range from 68 to 100 with an average of 91.9.According to the Neer results,18 cases were rated excellent,6 good,1 ordinary,and 1 poor.The rate ofexcellent and good were 92.3%.Conclusion Adult Neer Ⅳ proximal humerus fractures are mostly caused by high energy injuries,and usually with high rate of associated humeral head dislocation.The treatment of open reduction and locking plate internal fixation ensure favorable prognosis.Treatment effect is affected by several factors,such as the fracture degree,operation process,and rehabilitation training.A relatively higher location of the major tubercle of humerus causes the shoulder collision injury,which will has long-term impact on extension and upward movement of the shoulder joint.Underestimation of reconstruction of the proximal humerus medial pillar may cause humeral head varus and sink after operation.The arthralgia of the humeral head ischemic necrosis is less severe comparing to that of the femur head of lower limbs.And the humeral head ischemic necrosis is not necessarily the cause of shoulder joint malfunction.